1. Field of the Invention
The present invention is generally in the field of power plants. More specifically, the present invention is in the field of hydrokinetic turbines with means to adapt to changes in streamline direction and magnitude of a free flowing motive fluid.
2. Description of Prior Art
For over two thousand years mankind has known of harnessing the kinetic energy in flowing water to perform mechanical endeavors. In the past two hundred years the pace in which developments emerged in the practice of hydraulics has accelerated. The advent of the turbine in the first half of the nineteenth century culminated in the present advancements in hydroelectric generation, with this period of innovation and intense interest peaking in the first quarter of the twentieth century. Since then, fossil fuels have dominated as the high net energy, readily available energy source in the production of electricity and other conveyors of power. With known fossil fuel reserves at what presently appears to be arguably half depleted, as well as the environmental impact of using a polluting energy source, there is a strong need to develop a renewable and sustainable source of energy to support humankind.
Presently the hydroelectric power plant industry earns revenues of approximately thirty billion dollars annually, but unfortunately is in a state of decline mainly due to the environmental and civic costs of implementing the existing technology. Environmental impact of the prior art hydroelectric power plant threatens extinction to aquatic species living downstream from the proposed power plant infrastructure, and also displaces all human inhabitants that live in what would become the flood plane of the infrastructure. It is estimated that over sixty million people have been displaced in the past century due to hydraulic power plant development with no mention of the number of species of plant and animal that have gone extinct. Furthermore, given the prior art technology, there still exists the possibility of life threatening flooding occurring downstream from the site of the hydraulic power plant infrastructure. Overall these costs have weighed heavily in civic planners' decisions in adopting hydroelectric power generation to the point of putting the industry in a state of such decline that leading companies involved in this business are contemplating other areas of endeavor.
Inherent problems in the prior implementation of hydroelectric power generation have exacerbated the present state of declining interest in this technology. The earliest implementation of hydrokinetic systems, commonly known as waterwheels, allowed less impact to the natural flow of the body of water from which these systems drew energy. With the greater efficiency gained by enclosing the impeller within the turbine came the need for more sophisticated penstock arrangements, which included greater infrastructure in the form of dams incurring the majority of the civil and environmental costs. The penstock, gate and impeller arrangements for these systems are physically coupled to sustain a given range of flow velocities and pressures over varying head and load so to maintain required synchronization to the end electrical alternating current output. This requirement imposes on these systems almost exclusive implementation in fresh-water systems with large scale infrastructure, increasing impingement on human habitats, and for the most part, neglecting the significant kinetic energy recoverable from one or more of various forms of oceanic flow.
Other prior art exists where the motive fluid is ocean water, but still requires significant infrastructure. In one form, dam like structures known as barrages compel tidal flow to affect a turbine. Some turbines exist that operate in free flow, but do not adapt to changes in direction and have limited capacity, typically less than a kilowatt. In another recently developed form, offshore platform structures behave as pistons on waves at medium depths, in turn pumping a motive fluid through a turbine and then requiring a long distance power cable generally carrying high voltage direct current back to shore, to be further processed. This likely incurs significant maintenance costs for the offshore platforms. Fully implementing this prior technology would likely impede shipping lanes as a farm of these platforms effectively fences the shoreline. This stands as one of several known environmental impacts of this prior technology with others hypothetically existing.
When one amortizes the total amount of energy that goes into building and maintaining a prior art hydroelectric power installation, it becomes obvious that it takes a considerable amount of time before the plant becomes net energy positive, or in other words, the point when the total investment of energy compared to the total recovery of energy is at the break-even point. As a further example, fossil fuel, not being a renewable resource, requires mining or drilling deeper and pumping farther to obtain a lower yield and lower quality of fuel incurring more costly refining to recover the remaining reserves at the end-of-life of a mine or a well. Thus, fossil fuel as an energy source clearly diminishes in net energy as time goes on, until it obviously becomes a sink, no longer a source. This latter example reinforces the inevitability of mankind's undeniable need for a sustainable and renewable source of energy. Contemplating the net energy curves of a renewable energy source and fossil fuel indicates a sense of urgency for the development of a renewable source. The timing of the cross-over point of when one source becomes net energy positive as the other becomes net energy negative will dictate the severity of the ensuing energy crisis and thus the impact on humanity. As time goes on it will be less likely an option to expend a great deal of energy as an investment while more mundane needs are no longer being met. Despite this sense of urgency in the need to develop renewable, sustainable sources of energy, as previously stated hydroelectric power plant development is actually declining.
Therefore, there exists a fundamental need for developing renewable and sustainable sources of energy including further exploitation of readily available known resources. More specifically, there exists a need for a novel approach to ensure low impact to environment and low civic infrastructure costs such that the energy investment return is most quickly realized. Utmost, to optimally exploit oceanic energy, such as that which arrives onshore, adaptability to inherently unsteady flow is prerequisite of any such system. A system that can achieve the above-specified goals would readily attain a relatively high net energy soon after its inception.